THIS was not there LAST NIGHT when I changed 50% of his water. It was not there this morning when I fed him and admired him. It was not there this afternoon. Suddenly it is there. Grey, he has never had grey on his body ever. Please help.
is this fin rot? all his fins look so ragged all of the sudden. I don't understand! I keep my fish in impeccable conditions!

he has been lethargic as of late but i thought it was because he wasn't eating enough. he is always hungry and I was only feeding him 3 or 4 pellets twice a day. he's 3.75 inches long. i discovered he should be eating more so i just today started feeding him more and he's perked up. been swimming back and forth, flaring at esmeralda. the usual. he still did take a couple of naps but I thought that was normal. He has always been beautiful. show quality if VTs were allowed. Perfect, very full fins. all of the sudden they are ragged and turning green to grey to black.